The present invention relates to a process for preparing compositions useful as fuel and lubricant additives. More specifically, the process involves the condensation of a glyoxylic reactant with a hydrocarbyl substituted aromatic compound having at least one hydroxy functionality.
U.S. Pat. No. 5,281,346, Adams et al., Jan. 25, 1994 discloses a lubricant additive for two-cycle engines, said additive comprising at least one compound of the general formula EQU A.sup.y- M.sup.y+ (I)
wherein M represents one or more metal ions, y is the total valence of all M and A represents one or more anion counting groups having a total of about Y individual anionic moieties and each anion containing group is a group of the formula ##STR2## wherein T is selected from the group consisting of ##STR3## The products of formula (I) have been disclosed to be readily prepared by use of a carboxylic reactant, an embodiment of which was glyoxylic acid, represented in its hydrated form as EQU (HO).sub.2 CH--COOH PA1 (I) providing the glyoxylic reactant in the form of a compound represented by the formula ##STR5## or a reactive equivalent thereof, wherein R.sup.1 and R.sup.3 independently are hydrogen or hydrocarbyl group of 1 to about 4 carbon atoms; and R.sup.2 and R.sup.4 independently are hydrocarbyl groups of 1 to about 4 carbon atoms; PA1 (II) mixing the aromatic compound with the glyoxylic reactant; and PA1 (III) heating the mixture to a temperature of about 50.degree. C. to about 200.degree. C. in the presence of an acid catalyst for a sufficient time to form said condensation product. PA1 (1) hydrocarbon substituents, that is, aliphatic (e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, and aromatic-, aliphatic-, and alicyclic-substituted aromatic substituents, as well as cyclic substituents wherein the ring is completed through another portion of the molecule (e.g., two substituents together form an alicyclic radical); PA1 (2) substituted hydrocarbon substituents, that is, substituents containing non-hydrocarbon groups which, in the context of this invention, do not alter the predominantly hydrocarbon substituent (e.g., halo (especially chloro and fluoro), hydroxy, alkoxy, mercapto, alkylmercapto, nitro, nitroso, and sulfoxy); PA1 (3) hetero substituents, that is, substituents which, while having a pre-dominantly hydrocarbon character, in the context of this invention, contain other than carbon in a ring or chain otherwise composed of carbon atoms. Heteroatoms include sulfur, oxygen, nitrogen, and encompass substituents as pyridyl, furyl, thienyl and imidazolyl. In general, no more than two, preferably no more than one, non-hydrocarbon substituent will be present for every ten carbon atoms in the hydrocarbyl group; typically, there will be no non-hydrocarbon substituents in the hydrocarbyl group.
U.S. Pat. No. 5,458,793, Oct. 17, 1995 discloses a process comprising first forming an intermediate by reacting at an elevated temperature (a) at least one reactant of the formula ##STR4## with (b) a carboxylic reactant of the formula EQU R.sup.1 CO(CR.sup.2 R.sup.3).sub.x COOR.sup.10
and then reacting the intermediate so formed at a temperature ranging from about 100.degree. C. to about 250.degree. C. with an amine of the formula EQU H--X--(CR.sub.2.sup.f CR.sub.2.sup.f)--NH.sub.2
Glyoxylic acid is the preferred embodiment of the carboxylic reactant.
U.S. Pat. No. 5,560,755, (Adams et al., Oct. 1, 1996), 5,336,278 (Adams et al., Aug. 9, 1994) and 5,356,546 (Blystone et al., Oct. 18, 1994) disclose intermediates for fuel compositions prepared by reacting polybutene-substituted phenol and gloxylic acid in the presence of para-toluene sulfonic acid.
European Patent Application, EP 0779,355 A2, Kocsis et al., Jun. 18, 1997 discloses that lubricants which comprise, as an additive a salt of the reaction product of (i) glyoxylic acid or a hydrocarbyl substituted glyoxylic acid and (ii) a hydroxyaromatic compound, at least a portion of the molecules of which are alkylsubstituted, are useful for lubricating ceramic-containing engines, high temperature engines, and natural gas-fueled engines. Reactive equivalents of glyoxylic acid are disclosed to be acetals, half-acetals, esters, and the like.